1. Field of the Invention
The present invention relates to a ventilating fan, and particularly to a heating and ventilating fan.
2. Description of the Related Art
FIGS. 1A and 1B are schematic views of an existing heating and ventilating fan. As shown in FIGS. 1A and 1B, the heating and ventilating fan 15 comprises a frame 151, a motor 152 with fan blades, a casing 153, a heating device 154, an air path switching plate 157 disposed at an air outlet 155 of the casing 153 for switching outlets of the ventilating fan, and a stepping motor 158 for driving the air path switching plate 157 to rotate. When the heating and ventilating fan 15 operates, a circuit board sends a signal to control the stepping motor 158 to rotate, thereby driving the air path switching plate 157 to rotate. When the heating and ventilating fan 15 operates in a heating mode, the air path switching plate 157 blocks the ventilation outlet 159 of the frame 151, air is sucked from a suction port 156 of the heating and ventilating fan, passes the heating device 154 and then flows into a room for achieving the function of heating. When the heating and ventilating fan operates in a ventilation mode, the air path switching plate 157 blocks the heating outlet 160 of the frame 151 and air flows out of the room along an adapter for achieving the function of ventilation.
In the above prior art heating and ventilating fan for a bath room, it is necessary to send a signal to the stepping motor 158 by the circuit board, and then control the air path switching plate 157 to rotate by the stepping motor 158. As a result, a cost of the heating and ventilating fan is increased by employing the circuit board, the stepping motor and relevant components.